山西云中山-关帝山地区界河口岩群岩石学特征、LA-ICP-MS锆石U-Pb年龄及其归属

山西吕梁山地区界河口岩群（后文简称界河口群）主要由一套变质砂泥质岩石组成,含有一定量的条带状大理岩、斜长角闪岩等。利用LA-ICP-MS对位于关帝山西榆皮、娄烦县杜交曲及云中山三角镇地区的含石榴黑云二长花岗片麻岩（12LL05-1）、片状黑云母石英岩（12LL09-2）和含石榴钾长石英岩（12LL15-1）进行锆石U-Pb年龄测定,获得的二长花岗片麻岩（12LL05-1）岩浆结晶年龄为1941±28Ma、片状黑云母石英岩（12LL09-2）碎屑锆石最小的峰值年龄为2519.5±6.7Ma及含石榴钾长石英岩（12LL15-1）碎屑锆石2个峰值年龄2143±15Ma和2599±11Ma。根据岩石组合和同位素测定结果推测,关帝山西榆皮地区的界河口群与界河口-汉高山一带的界河口群可以对比,沉积时代在1.94Ga之前;娄烦县杜交曲一带的界河口群可与五台岩群相对比,属新太古代;云中山三交镇一带的界河口群可与野鸡山群或岚河群相对比。沿岚县-方山-吕梁一线存在一条大型韧性剪切带,倾向NNW-NWW,表现为右行剪切的运动学性质,将吕梁山区近EW向构造带改造为NNE向。     

中新世以来吕梁山及邻区构造——沉积演化

裂变径迹研究显示中新世早期(23±3Ma)现今吕梁山及周缘地区发生了一次整体性快速隆升。中新世晚期(约8Ma前),吕梁山前、鄂尔多斯盆地及东部宁武—沁水盆地结束了长期剥蚀历史,开始广泛接受新生代沉积。沉积物的垂向叠置关系及横向展布特征显示:8.35～6.7Ma为吕梁山快速差异隆升期,在山前(东西两侧)堆积了冲积扇相芦子沟组砾岩层,暗示了吕梁山已经地貌上成山;与此同时地势相对平坦且摆脱地表水流影响的鄂尔多斯盆地广泛堆积了风尘堆积—红黏土(保德组)。中新世晚期—早更新世早期(6.7～1.8Ma),吕梁山西部山前及鄂尔多斯地区整体缓慢隆升,堆积了新近纪保德组上部、静乐组红黏土及早更新世午城组黄土—古土壤序列。受西部六盘山快速抬升作用影响,鄂尔多斯西部抬升速率略高于东部,于早更新世中期(1.8～1.4Ma)形成现今西高东低的地势格局和南北向晋陕谷地,进而黄河及其支流顺流而下。中更新世以来,鄂尔多斯地区沉积与抬升并重,最终形成现今黄土高原。吕梁山以东的沁水盆地中新世演化史与西部相似,上新世起盆地开始断陷,汾河地堑开始形成。断陷一直持续到早更新世,自下而上依次沉积了下土河组、小白组、大沟组、木瓜组湖相地层,盆地边缘则持续抬升堆积了静乐组和午城组风成堆积。中更新世以来,断陷结束,盆地整体抬升。     

构造物理化学成矿理论问题探讨

构造物理化学成矿研究涉及以下新的认识:构造体制下矿源岩系演化序列,构造动力热液淬取成矿机制,构造附加动力驱动热液成矿机制,构造应力场转化成矿机制,成矿流体水-岩反应的浓缩成矿机制以及构造物理化学场结构与界面成矿特点。     

黄土丘陵区沙棘群落天然化发育过程中植物物种多样性研究

运用空间代替时间的方法,对黄土丘陵沟壑区不同发育阶段(3 a、8 a、15 a、25 a)的沙棘人工林群落内植物的种类、盖度、密度等进行调查,并分析了沙棘人工林群落天然化发育过程中物种多样性动态变化。结果表明:1.沙棘人工林群落天然化发育过程中主要以菊科、禾本科、豆科植物为主。其生活型变化为:一年生草本群落→多年生草本群落→半灌丛群落→灌丛群落。2.不同发育阶段沙棘群落灌木层物种丰富度呈增加趋势,草本层的物种丰富度呈先减少后增加的趋势;灌木层和草本层的S impson指数和Shannon-W iener指数在不同阶段沙棘群落中表现出大致相同的趋势,即草本层>灌木层。同一层次的物种多样性指数D和H′虽然数值不同,但在不同发育阶段有基本一致的趋势。草本层多样性指数在荒草地阶段较高,其他阶段的沙棘群落随发育时间的增加而减少;灌木层物种多样性指数随发育时间的增加而呈波动性增加。3.随着群落发育,群落相似性增加。总体上,随着沙棘群落的发育,不同科属的植物种类在增加,群落生态优势度增加,到15 a时群落趋向稳定。     

大容量存储器K9K8G08U0A及其在定点垂直升降剖面测量系统中的应用

介绍了新型大容量存储器K9K8G08U0A的基本组织结构,重点讲述了存储器与ATmega128L单片机外部存储器接口的硬件连接方式以及存储器的主要操作流程和部分C语言代码。     

浮游生物光学计数器(OPC-1L)精度控制关键问题研究

浮游生物光学计数器（Optical Plankton Counter,OPC）能够在现场和实验室内对浮游动物、鱼卵和其它水生生物进行实时的数量统计和粒径划分,可以有效地替代繁琐的传统人工计数,快速获得丰度和生物量（体积）谱数据。但在实际应用中会存在很多问题,特别是如何进行标定和消除由于操作方法而引起的误差,这些问题的存在与解决,直接影响到观测数据的准确性和可靠性,以及能否利用此仪器进行快速、有效的浮游生物长时间序列监测与分析。本研究中作者针对计数过程中气泡干扰和样品重叠的问题,对进样系统进行了改良,通过大量实验研究了准确率与进样速度、生物形状之间的关系,探讨了如何通过速度控制有效提升准确率。通过改进循环水系统并加装相应的外围设施,使气泡问题得以解决。通过一系列的对比试验发现,控制Dmax（最大测样速度）在11个／s以内,可以使重合率维持在5％以下;控制Dmax在7个／s以内,可以使重合率降低到2％以下。同时发现生物的形状也会影响测量精度。结果表明,无论在何种测样速度下,随着长宽比（L/W）的增加,ESD（Equivalent Spherical Diameter,遮挡相同数量光线的球的直径）均值准确度均出现“V”形变化,先降低后增加,在L／W为4或6时准确度达到最低。本研究中作者有效解决了气泡干扰的问题,根据所确定的参数和目标种群体型相结合,选择合理的进样速度,完全能够达到98％以上的数量准确度和95％的ESD均值准确度。     

A new orbit for comet C/1858 L1 (Donati)

A new orbit for comet C/1858 L1 (Donati), based on 1036 observations in α and 971 in σ made between 7 June 1858 and 5 March 1859, is calculated using iteratively reweighted least squares. Residuals were weighted by the Welsch weighting function. The orbit represents a high eccentricity ellipse, e = 0.996265, with large semi‐major axis, a = 154.8612 AU, and long period, P = 1927.22 yr. The residuals are relatively random, a 10.7% chance of being random, but with a slight indication of possible nongravitational forces influencing the motion. The comet will not return until the year 3759, when it will pass 0.8442 AU from the Earth. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

川蔓藻在湖泊水位重建和环境变化研究中的应用

沉水被子植物川蔓藻广泛分布于海湾、泻湖、河口湿地以及内陆湖泊、沼泽、湿地中,是水生动物重要的食物和栖息地,具有改善水质和保护堤岸的作用。由于川蔓藻只能在小于0.5~4m深的浅水环境中生存,因此原地保存在湖泊沉积物中的化石种子可作指示古湖水深的定量指标。该项指标在闭流型湖泊水位重建和气候变化研究中有着不可忽视的重要作用。科学管理川蔓藻,对水体环境的改善、海洋污染的治理和湿地生物多样性下降的缓解具有重要价值。     

Chronology of Early to Mid-Pleistocene sediments in the northern North Sea: New evidence from amino acid and strontium isotope analyses

Sediments deposited during glacial-interglacial cycles through the Early to Mid-Pleistocene in the North Sea are chronologically poorly constrained. To contribute to the chronology of these units, amino acid racemization (AAR) and strontium (Sr) isotope analyses have been performed on samples from four shallow borings and one oil well along a transect in the northern North Sea. D/L Asp (aspartic acid) values obtained through reverse-phase liquid chromatography in the benthic foraminiferal species Elphidium excavatum is focused on because of consistent results and a good stratigraphic distribution of this benthic species. For the Early Pleistocene, an age model for the well 16/1–8, from the central part of the northern North Sea based on Sr ages allows for dating of the prograding wedges filling the pre-Quaternary central basin. A regional calibration curve for the racemization of Asp in Elphidium excavatum is developed using published ages of radiocarbon-dated samples and samples associated with the previously identified Bruhnes/Matuyama (B/M) paleomagnetic boundary and a Sr age from this study. Based on all the available geochronological evidence, samples were assigned to marine oxygen isotope stages (MIS) with uncertainties on the order of 10–70 ka.Sr ages suggest a hiatus of <2 million years (Ma) possibly due to non-deposition or low sedimentation between the Utsira Formation (Pliocene) and the Early Pleistocene. An increase in sedimentation rates around 1.5 ± 0.07 Ma (∼MIS 51) may partly be due to sediment supply from rivers from the south-east and partly due to the extension of ice sheet around 1.36 ± 0.07 Ma from the Norwegian coast to the central North Sea. A possible basin-wide glaciation occurred around 1.1 Ma (∼ MIS 32) (upper regional unconformity/top of unit Q4 in this study), resulting in erosion and regional unconformity. Two interglacials in the Norwegian Channel have been dated: the Radøy Interglacial to 1.07 ± 0.01 Ma (possibly MIS 31, the ‘super interglacial’), and the Norwegian Trench Interglacial to 0.50 ± 0.02 Ma (possibly MIS 13). A massive till unit identified at the same stratigraphic level in all shallow borings may partly represent an extensive MIS 12 glaciation. This study shows that the combined use of amino acid racemization data and Sr isotope chronology can refine the chronological ambiguities of Quaternary North Sea sediments related partly to the impact of glacial processes.